Prefabricated metal staircase

ABSTRACT

The present invention relates to a prefabricated metal staircase which may be assembled from structural members comprising extruded elements which may be made of aluminium. Staircases in accordance with the invention may serve as fixed permanent staircases or as temporary or emergency staircases and may be very versatile in view of the ease and rapidity with which they may be assembled and in view of their adaptability to provide whatever angle is required to meet the local situation.

United States Patent L191 Loix Oct. 16, 1973 [54] PREFABRICATED METAL STAIRCASE 3,150,742 9/1964 Carter 52/184 [161 Inventor: Gilbert we Chaussee Bmmham 5283322 55133? 3223;251:1311; ...:""53

22, Wihogne, 4462 Belgium [22] Filed: Nov. 26, 1971 Primary ExaminerHenry C. Sutherland Assistant Examiner-H. E. Raduazo [21] Appl' 202082 Attorney-R0bert E. Burns et a1.

[30] Fgeiggn (application Priority Data 57] ABSTRACT 6c e 8mm 760 720 The present invention relates to a prefabricated metal [52] US. Cl 52/182 182/228 52/588 staircase which may be assembled from structural [51] Int n 2 11/12 members comprising extruded elements which may be 581 Field of searchl l ffjl fff111111.32/182484 made aluminium Staircases in acwdance with 52/188 191 182/228 invention may serve as fixed permanent staircases or as temporary or emergency staircases and may be very ile in view of the ease and ra idity with which [56] References Cited versat p they may be assembled and in view of their adaptabil- UNITED STATES PATENTS ity to provide whatever angle is required to meet the 538,145 4/1895 Allen 52/182 l l Situation 1,593,360 7/1926 Richmond. 52/191 1,676,317 7/1928 Bennett 52/191 13 Claims, 3 Drawing Figures PATENTEB OCT 1 6 I975 SHEET E OF 2 PREFABRICATED METAL STAIRC ASE A staircase in accordance with the invention is characterised in that it is "constituted by the assembly of extruded sections'cut to the measurements appropriate to the staircase characteristics required.

More particularly, the invention provides a staircase constituted by an assembly or prefabricated components including a plurality of extruded sections cut to lengths to provide structural members appropriate to the size of the staircase, wherein the assembly comprises a pair of stringers or side members each provided by one form of said extruded sections having a hollow cross-section in the shape of a figure 8, the inner side wall of each said stringer or side member having mounted thereon a pair of longitudinal members provided by a second'form of said extruded sections, each longitudinal member having therein a plurality of holes at positions appropriate to the staircase angle adopted, said holes being fitted with projecting elements, each projecting element of one longitudinal member being related to a projecting element of the other longitudinal member so as to provide a pair adapted collectively to support one end of a step member which extends between the stringers or side members and which is provided by a third form of said extruded sections, said step member being capable of adapting itself to the distance between said pair of projecting elements which distance varies according to the angle adopted for the staircase. i

It hasheretofore been proposed particularly in US.

Pat. No. 3,499,254 to provide aprefabricated staircase adaptable to local requirements by modifying the height of the risers, the latter being provided by two parts, one part being integral with a lower step and the other being integral with an upper step. In such prior proposed structure, however, projecting elements are directly placed and bolted inside stringer members and the use of a side covering plate and of a large number of different and complex-shaped sections was necessary.

The manner in which the present invention may be put into practice will now be described in more detail,

by way of example, with reference to the accompanying drawings wherein:

FIG. 1 is a fragmentary perspective and partsectional view of one form of staircase assembly constructed in accordance with the invention;

FIG. 2 is a vertical section through one side of the staircase assembly of FIG. I with the step, shown in the latter Figure, being omitted; and

FIG. 3 is a vertical cross-sectional view of the step shown in FIG. 1.

Referring to the drawings, the stiarcase assembly in accordance with the invention shown therein includes three kinds of extruded sections which provide constituent structure members and which may be composed on an aluminium metal.

The first kind of section is used to provide two main side members or stringers of which one, denoted by the reference numeral 1, is illustrated in the drawings. The section of these stringers has a hollow box-like formation in the shape of a figure 8" and the side wall which is intended, in use, to be presented inwardly to confront the stairway is formed, towards top and bottom respectively, with longitudinally-extending openings or slots 2,2, of whichthe edges are provided with grooves 3 (see FIG. 2) and form a slideway.

In each of these openings or slots 2, 2, is fitted a slide member 4 constituted by a second kind of extruded hollow section having a pair of oppositely projecting tongues S, 5, which engage in the grooves 3 and having also ribs or projections 6 which engage over an internal flange portion 7 bounding the slideway openings or slots 2, 2.

The third kind of extruded section is used to provide the members forming the steps of the staircase of which one is indicated at 8'. The main portion of this section has a substantially plane profile with opposite edge portions 9 and '10 which extend downwards and inwards as shown in FIG. 3. Underneath the main flat portion, a

pair of depending spaced-apart flanges 11, 11', are provided towards the front edge 9. The section is also provided with a depending central stiffening web 12 and with a plurality of depending support projections, 13

towards the front edge between flanges ll, 11', and

13a, 13b, 13c, 13d, 13c, and 13f, towards the rear edge. Also, the edge portions 9 and 10 are provided with various projections forming grooves 14 for a purpose hereinafter to be explained.

The number of the rear support projections, 13a, 13b, 13c, 13d, Be, and 13f, could if desired, be limited to a smaller number such as four for example, but the greater number provided in this example can increase the possible adaptability'of the staircase.

ln order to produce staircases in accordance with the invention, it is sufficient to form, by extrusion, the three different kinds of section which are then cut to the lengths required to provide the individual members 1, 4 and 8, to suit the size of staircase required, and then to assemble these members.

Before fitting the slide members 4 into the slideway slots 2 of the stringers '1, a series of regularly spaced pairs of holes, 15 and 15' through the outer and inner side walls 4' and 4 respectively are drilled in positions appropriate to the angle to be adopted for the staircase. As shown in FIG. 2, the holes 15 in the outer walls 4' are of greater diameter than the holes 15' in the inner wall 4".

The holes 15 are adapted to receive tube parts 16 which serve as supports for the step members 8. Each tube part received in a hole 15 lies inside the slide member 4 and its end abuts the inner wall 4 opposite the corresponding hole 15', and a bolt 17 is introduced through the latter. The bolt 17 extends through the tube part 16 and projects at the opposite end where it is fitted with a washer l8 engaging the tube part, with a tube clamping nut 19, with a step fixing clamp member 20 and with a fixing nut 21.

After the slides 4, fitted with the step support tube parts 16, are introduced into the slideway slots 2 of the stringer members 1, the stop members 8 are each mounted on the support tube parts 16 in the following manner. First, the rear edge 10 of the step member 8 is hooked around a pair of opposed tube parts 16 which project from the stringers forming opposite sides of the stairway and which are mounted in the lower slide members 4 of the latter. The front edge 9 of the step member is then applied over a pair of corresponding opposed tube parts 16 which are mounted in the upper slide members 4 of the stringers, in such a manner that these tube parts fit between flanges l l, 11', of the step member. A good seating of the step member is obtained by the support porjections 13 and 13a, 13b, 13c, 13d, 13s and 13f which contact the tube parts. The tube parts in the lower slide members 4 are confined, as shown in FIG. 3, between the rear support projections and the folded lower portion of the rear edge 10. According to the inclination of the stringers 1, those lower tube parts can occupy a different position within the rear folded portion of the step member and contact difierent projections of the series 13a, 13b, 13c, 13d, 13e and 13f.

Clamping of the step members 8 on the supporting tube parts 16 between the stringers is achieved by means of the members 20 and the nuts 21, cut-outs or apertures to allow positioning of the members 20 being provided in the flanges 11, 11' and also in'the folded lower portion of the rear edge 10. A clamping of the step members is thereby achieved externally to the stringers.

When the elements of the staircase have been assembled as shown diagrammatically in FIG. 1, plates may then be placed beneath the step members and also, to form risers, between adjacent step members, said plates being fitted into the appropriate grooves 14 (as indicated by the thick broken lines in FIG. 3) thereby to obtain a well-closed stairway assembly. The underside closure plates may be supported towards the middle by the web portion 12.

The top main portions providing the tread of the step members can be provided with a non-slip surface as indicated at 8'. This may be formed in extruding the section or it may be added subsequently.

It will readily be understood that, having a stock of the three kinds of sections to provide the members 1, 4 and 8, and of tube parts 16 and bolts 17, and knowing the necessary information about the required staircase, the latter can then be assembled very quickly.

if desired, the top face or wall of each of the stringer members 1 can be provided with a plurality of regularly spaced apertures 22 for the fitting of balustrade rails.

It will, of course, be understood that many other modifications can be made and the profile of the sections can be varied from the exact form described and illustrated in the accompanying drawings within the scope of the invention as defined in the appended claims.

What 1 claim is:

l. A staircase assembly of prefabricated components composed of a plurality of extruded sections cut to predetermined lengths to provide structural members ap propriate to the size of the staircase, said assembly comprising a pair of stringers or side members each comprising one of said extruded sections having a hol low cross-section in the shape of a figure 8 and each having mounted on an inner side wall a pair of longitudinal members comprising another of said extruded sections, each longitudinal member having therein means defining a plurality of holes at predetermined positions determined by the staircase angle adopted, a plurality of projecting elements each disposed in one of said holes, each projecting element of one longitudinal member coacting with a projecting element of the other longitudinal member to provide a pair of supports, a step member comprising a further one of said extruded sections extending between said pair of stringers or side members and supported-by said projecting elements, said step member having means for adapting itself to the distance between said pair of projecting elements comprising said pair of supports.

2. A staircase in accordance with claim 1, including means defining a pair of slideways in each stringer of said pair of stringers, one slideway disposed near the top of said stringer and the other slideway disposed near the bottom of said stringer, and wherein said longitudinal members are each mounted in one slideway.

3. A staircase in accordance with claim 1, wherein said step member has a main upper portion with a substantially plane surface and front and rear edge portions which extend downwards and inwards.

4. A staircase in accordance with claim 3, including means defining a pair of spaced flanges projecting from the underside of said step member, and wherein the rear edge portion of each said step member comprising means for embracing the associated supporting projecting elements of the lower longitudinal members of the stringers or side members, and wherein the relates supporting projecting elements of the upper longitudinal members of the stringers or side members comprising means fitable between said pair of spaced flanges.

5. A staircase, in accordance with claim 1, wherein said projecting elements comprise tube parts inserted into said holes in said longitudinal members.

6. A staircase, in accordance with claim 5, including a bolt extending through said tube parts forming the supporting projecting elements, said bolt having a head end disposed adjacent the respective longitudinal member and an opposite end projecting from the end of the tube part under the step member, said opposite end having a clamping or fixing member for engaging said step member.

7. A staircase in accordance with claim 6, wherein said spaced flanges of each step member have means therein defining cut-outs or openings for accommodating said clamping or fixing member of said bolts of said supporting tube parts of said upper longitudinal members of said stringers or side members.

8. A staircase in accordance with claim 4 including means defining a plurality of support members projecting from the underside of said step member near the rear edge portion of said step member, each support member having means contactable in supporting relationship with one of said supporting tube parts.

9. A staircase in accordance with claim 3 including means in the front and rear edge portions of each said step member defining a plurality of grooves for receiving therein closure plates for closing the underside of the step member and for providing risers.

10. A staircase in accordance with claim 9, including means in the underside of the main upper portion of said step member defining a centrally disposed web stiffener for stiffening said step member and for supporting an underside closure plate.

11. A staircase in accordance with claim 1, wherein said step member has means defining a non-slip surface.

12. A staircase in accordance with claim 1, wherein. the top of each of said stringers or side members has means therein defining a plurality of apertures for fitting therein a balustrade rail.

13. A staircase in accordance with claim 1, wherein said extruded sections are composed of aluminium.

b i i Q t 

1. A staircase assembly of prefabricated components composed of a plurality of extruded sections cut to predetermined lengths to provide structural members appropriate to the size of the staircase, said assembly comprising a pair of stringers or side members each comprising one of said extruded sections having a hollow cross-section in the shape of a figure ''''8'''' and each having mounted on an inner side wall a pair of longitudinal members comprising another of said extruded sections, each longitudinal member having therein means defining a plurality of holes at predetermined positions determined by the staircase angle adopted, a plurality of projecting elements each disposed in one of said holes, each projecting element of one longitudinal member coacting with a projecting element of the other longitudinal member to provide a pair of supports, a step member comprising a further one of said extruded sections extending between said pair of stringers or side members and supported by said projecting elements, said step member having means for adapting itself to the distance between said pair of projecting elements comprising said pair of supports.
 2. A staircase in accordance with claim 1, including means defining a pair of slideways in each stringer of said pair of stringers, one slideway disposed near the top of said stringer and the other slideway disposed near the bottom of said stringer, and wherein said longitudinal members are each mounted in one slideway.
 3. A staircase in accordance with claim 1, wherein said step member has a main upper portion with a substantially plane surface and front and rear edge portions which extend downwards and inwards.
 4. A staircase in aCcordance with claim 3, including means defining a pair of spaced flanges projecting from the underside of said step member, and wherein the rear edge portion of each said step member comprising means for embracing the associated supporting projecting elements of the lower longitudinal members of the stringers or side members, and wherein the related supporting projecting elements of the upper longitudinal members of the stringers or side members comprising means fitable between said pair of spaced flanges.
 5. A staircase, in accordance with claim 1, wherein said projecting elements comprise tube parts inserted into said holes in said longitudinal members.
 6. A staircase, in accordance with claim 5, including a bolt extending through said tube parts forming the supporting projecting elements, said bolt having a head end disposed adjacent the respective longitudinal member and an opposite end projecting from the end of the tube part under the step member, said opposite end having a clamping or fixing member for engaging said step member.
 7. A staircase in accordance with claim 6, wherein said spaced flanges of each step member have means therein defining cut-outs or openings for accommodating said clamping or fixing member of said bolts of said supporting tube parts of said upper longitudinal members of said stringers or side members.
 8. A staircase in accordance with claim 4 including means defining a plurality of support members projecting from the underside of said step member near the rear edge portion of said step member, each support member having means contactable in supporting relationship with one of said supporting tube parts.
 9. A staircase in accordance with claim 3 including means in the front and rear edge portions of each said step member defining a plurality of grooves for receiving therein closure plates for closing the underside of the step member and for providing risers.
 10. A staircase in accordance with claim 9, including means in the underside of the main upper portion of said step member defining a centrally disposed web stiffener for stiffening said step member and for supporting an underside closure plate.
 11. A staircase in accordance with claim 1, wherein said step member has means defining a non-slip surface.
 12. A staircase in accordance with claim 1, wherein the top of each of said stringers or side members has means therein defining a plurality of apertures for fitting therein a balustrade rail.
 13. A staircase in accordance with claim 1, wherein said extruded sections are composed of aluminium. 